Jobs By Abekus

Heat-transfer Questions Set 9:

Quiz Mode

A body has an area of 0.68 m² and its effective temperature is 693 K. Find its total rate of energy emission.

8892.5 W

6785.9 W

9674.4 W

8543.7 W

Solution:

A 1 m long nichrome wire with a radius of 1.76 mm dissipates a power of 10 kW. Determine the rate of heat generation.

176 W/m^3

1027.64 W/m^3

0.176 W/m^3

11.76 W/m^3

Solution:

If the heat transfer rate is 323 kJ/s and the enthalpy of evaporation is 3568 kJ/kg, then find the rate of water evaporation.

325.89 kg/hr

0.0905 kg/hr

3891 kg/hr

3245 kg/hr

Solution:

Which of the following is not a true assumption of Fourier's law of heat conduction?

Steady state heat conduction

No internal heat generation

Isotropic and homogeneous material

Linear temperature profile

Solution:

A radiator in a domestic heating system operates at a surface temperature of 60 degrees Celsius. Calculate the heat flux at the surface of the radiator if it behaves as a black body.

697.2 W/m^2

786.9 W/m^2

324.7 W/m^2

592.1 W/m^2

Solution:

A window consists of two layers of glass, each with a thickness of 10 mm and thermal conductivities of 0.70 W/mK and 0.78 W/mK. Assume the area for both layers is 1 m². The overall thermal resistance is:

0.057 K/W

0.027 K/W

0.064 K/W

0.082 K/W

Solution:

Find the effectiveness of a heat exchanger if the mass flow rate specific heat product of both fluids is the same, and the hot fluid enters at 87°C and leaves at 66°C, while the cold fluid enters at 28°C and leaves at 58°C.

0.263

0.341

0.258

0.355

Solution:

Which fin arrangement is better for heat transfer?

A. 5 fins of 8 cm length each

B. 10 fins of 4 cm length each

Given, the cross-sectional area of fins is the same and constant throughout.

Arrangement A

Arrangement B

Both give the same heat transfer rate

Insufficient Data

Solution:

What is the steady-state heat transfer rate per unit area through a 90 mm thick homogeneous slab with its two faces maintained at uniform temperatures of 80°C and 30°C respectively? The thermal conductivity of the material is 0.30 W/(m·K).

166.67 W/m²

218.87 W/m²

150.76 W/m²

170.67 W/m²

Solution:

In a parallel flow heat exchanger, the maximum possible heat transfer is given by:

Given: **mc(Cp)c < mh(Cp)h**

Where:

mc = mass flow rate of cold fluid

mh = mass flow rate of hot fluid

(Tc)i and (Th)i are inlet temperatures of cold and hot fluid respectively.

(Tc)o and (Th)o are outlet temperatures of cold and hot fluid respectively.

(Cp)c and (Cp)h are specific heat capacities of cold and hot fluid respectively.

Tm is the Logarithmic Mean Temperature (LMT).

mc*(Cp)c*(Thi - Tci)

mh*(Cp)h*(Thi - Tci)

mh*(Cp)h*Tm

mc*(Cp)c*Tm

Heat-transfer Questions Set 9:

A body has an area of 0.68 m² and its effective temperature is 693 K. Find its total rate of energy emission.

Solution:

A 1 m long nichrome wire with a radius of 1.76 mm dissipates a power of 10 kW. Determine the rate of heat generation.

Solution:

If the heat transfer rate is 323 kJ/s and the enthalpy of evaporation is 3568 kJ/kg, then find the rate of water evaporation.

Solution:

Which of the following is not a true assumption of Fourier's law of heat conduction?

Solution:

A radiator in a domestic heating system operates at a surface temperature of 60 degrees Celsius. Calculate the heat flux at the surface of the radiator if it behaves as a black body.

Solution:

A window consists of two layers of glass, each with a thickness of 10 mm and thermal conductivities of 0.70 W/mK and 0.78 W/mK. Assume the area for both layers is 1 m². The overall thermal resistance is:

Solution:

Find the effectiveness of a heat exchanger if the mass flow rate specific heat product of both fluids is the same, and the hot fluid enters at 87°C and leaves at 66°C, while the cold fluid enters at 28°C and leaves at 58°C.

Solution:

Which fin arrangement is better for heat transfer?

A. 5 fins of 8 cm length each

B. 10 fins of 4 cm length each

Given, the cross-sectional area of fins is the same and constant throughout.

Solution:

What is the steady-state heat transfer rate per unit area through a 90 mm thick homogeneous slab with its two faces maintained at uniform temperatures of 80°C and 30°C respectively? The thermal conductivity of the material is 0.30 W/(m·K).

Solution:

Solution:

Related Question Sets:

Related Topics:

Heat-transfer Questions Set 9:

A body has an area of 0.68 m2 and its effective temperature is 693 K. Find its total rate of energy emission.

Solution:

A 1 m long nichrome wire with a radius of 1.76 mm dissipates a power of 10 kW. Determine the rate of heat generation.

Solution:

If the heat transfer rate is 323 kJ/s and the enthalpy of evaporation is 3568 kJ/kg, then find the rate of water evaporation.

Solution:

Which of the following is not a true assumption of Fourier's law of heat conduction?

Solution:

A radiator in a domestic heating system operates at a surface temperature of 60 degrees Celsius. Calculate the heat flux at the surface of the radiator if it behaves as a black body.

Solution:

A window consists of two layers of glass, each with a thickness of 10 mm and thermal conductivities of 0.70 W/mK and 0.78 W/mK. Assume the area for both layers is 1 m². The overall thermal resistance is:

Solution:

Find the effectiveness of a heat exchanger if the mass flow rate specific heat product of both fluids is the same, and the hot fluid enters at 87°C and leaves at 66°C, while the cold fluid enters at 28°C and leaves at 58°C.

Solution:

Which fin arrangement is better for heat transfer? A. 5 fins of 8 cm length each B. 10 fins of 4 cm length each Given, the cross-sectional area of fins is the same and constant throughout.

Solution:

What is the steady-state heat transfer rate per unit area through a 90 mm thick homogeneous slab with its two faces maintained at uniform temperatures of 80°C and 30°C respectively? The thermal conductivity of the material is 0.30 W/(m·K).

Solution:

Solution:

Related Question Sets:

Related Topics:

A body has an area of 0.68 m² and its effective temperature is 693 K. Find its total rate of energy emission.

Which fin arrangement is better for heat transfer?

A. 5 fins of 8 cm length each

B. 10 fins of 4 cm length each

Given, the cross-sectional area of fins is the same and constant throughout.